Showing papers on "Micro heat exchanger published in 1972"

Extended surface heat transfer

Abstract: Preface. Convection with Simplified Constraints. Convection with Real Constraints. Convective Optimizations. Convection Coefficients. Linear Transformations. Elements of Linear Transformations. Algorithms for Finned Array Assembly. Advanced Array Methods and Array Optimization. Finned Passages. Compact Heat Exchangers. Longitudinal Fin Double-Pipe Exchangers. Transverse High-Fin Exchangers. Fins with Radiation. Optimum Design of Radiating and Convecting-Radiating Fins. Multidimensional Heat Transfer in Fins and Fin Assemblies. Transient Heat Transfer in Extended Surfaces. Periodic Heat Flow in Fins. Boiling From Finned Surfaces. Condensation on Finned Surfaces. Augmentation and Additional Studies. Appendix A: Gamma and Bessel Functions. Appendix B: Matrices and Determinants. References. Author Index. Subject Index.

Device for the absorption and emission of heat

Abstract: In a device for the absorption and release of heat, two largesurface elements are provided, of which one emits the heat and acts as a heat source and the other absorbs the heat and acts as a heat sink. These two large-surface elements are joined to each other with pipes connected in parallel which are in good heat conducting contact with the large-surface elements. The internal space of the pipes is closed and filled with a heat carrier in a state of saturated vapour within the operating range.

Temperature-control system with rotary heat exchangers

Abstract: An independently heated or cooled room is linked with an environment of different temperature through a fluid-circulation system including a closed path traversed by a heat-carrier medium. The medium travels between two heat exchangers, respectively located in the warmer and in the colder air, under a pressure differential low enough to maintain a coherent flow at substantially uniform speed in one or more pairs of channels extending between the two heat exchangers.

Condensation apparatus for steam turbine power plants

Abstract: Steam turbine power plants employ condensers for condensing the dead steam of the turbine. The required cooling in the condenser is obtained by cooling water which is, in case of dry cooling towers, injected into a mixing condenser. Recooling of the cooling water is obtained in surface heat exchangers of the dry cooling tower which carry off the heat by means of air. Where the employment of such system is jeopardised by the hazards of climatic conditions, it is suggested to associate water cooled heat exchangers with the surface heat exchangers and the dry cooling tower of the system. Such water cooled heat exchangers serve as auxiliary means where the cooling effect of the surface heat exchangers of the dry cooling tower fails to ensure a desired low condensation temperature in the mixing condenser.

Air conditioning installation

Abstract: An installation for conditioning air in an associated space, comprising at least two pairs of heat exchangers, each such pair including a surface heat exchangers and a mixing one, the second (in the direction of the flow of the air being treated through the apparatus) pair of heat exchangers communicating through the surface heat exchanger of the first pair with the conduit through which ambient air to be treated by the apparatus is supplied, for this air, after its having been cooled in the last-mentioned heat exchanger, to be directed for still deeper cooling into the surface heat exchanger and the mixing heat exchanger of the second pair.

Transient heat flow from a thin circular disk — small-time solution

Abstract: In a previous paper [1] an approximate analytical solution, useful for large times, was obtained for the transient heat flow from a thin circular disk held at constant temperature and immersed in an infinite medium. In the present work a first approximation has been found for the complementary \"small-time\" solution and the details of this solution examined. Some numerical calculations are included.

Heat pipe design handbook, part 1

Abstract: The development and characteristics of heat pipes are examined. The subjects discussed are: (1) principles of operation, (2) heat pipe theory, (3) pressure gradient effects, (4) variable conductance, (5) design procedure, and (6) performance limit evaluation.

Sludge separation systems employing refrigeration means

Abstract: A sludge separation system, particularly of the type for promoting separation of alum sludge from the effluent of a potable water treatment plant, is provided with a pair of identical falling film heat exchangers wherein sludge is distributed to flow down the interior of the heat exchange tubes of one of the heat exchangers and a cooling medium is circulated through the interior of the tubes in the other heat exchanger. A refrigeration system is provided to freeze sludge in the one heat exchanger by evaporating the refrigerant on the exterior of the heat exchange tubes. The evaporated refrigerant is compressed and condensed on the exterior of the tubes in the other heat exchanger. Recirculation means for sludge is provided in order to continuously cool and solidify a thin film of the sludge descending in the heat exchange tubes of the one heat exchanger and a similar recirculation means is provided for recirculating cooling medium through the heat exchange tubes of the other heat exchanger. Periodically the refrigeration system is reversed, utilizing the cooling capacity of the frozen sludge in the heat exchange tubes of the one heat exchanger to condense refrigerant while freezing sludge in the heat exchange tubes of the other heat exchanger. Means are provided to supply the separated liquid component of the sludge as an additional cooling medium in the heat exchanger acting as a refrigerant condenser so that it is unnecessary to provide a separate condenser.

The Design of Optimum Heat Exchangers for Dilution Refrigerators

Abstract: The behavior of discrete heat exchangers as a function of temperature, heat transfer area, and 3He flow rate is shown for a general case by means of some machine calculated curves. From these curves, the appropriate heat exchanger size can be determined for the various steps of a discrete heat exchanger. Also, curves for the mixing chamber temperature Tm as a function of total surface area divided by flow rate for various amounts of external heat to the mixer are shown for the continuous exchanger. From these curves the optimum 3He flow rate for a given heat input and exchanger size can be determined. Viscous heating has been included in the calculation of one typical coaxial tube exchanger. It is found that heating in the dilute stream has negligible effect on Tm, whereas the viscous heating in the concentrated side, though several times smaller than that in the dilute side, has considerably more effect on Tm. Based on this behavior, an improved method of ``heat sinking'' heat leak paths to the mixer is ...

Helical coil heat exchanger

Abstract: A heat exchanger, particularly applicable for transferring heat from a reactor-heated primary coolant circuit to a secondary coolant circuit, wherein the secondary coolant flows upward inside helical tubes in a counterflow arrangement with respect to the primary coolant, and the ends of the helical tubes are attached to tube sheets which are accessible from above for inspection and repair, and a method for locating and repairing leaking conditions. The invention is applicable, for example, as an intermediate heat exchanger in a sodium to sodium system for large liquid metal fast breeder reactors.

Heat exchanger with a removable tube section

Abstract: A heat exchanger in which the tube sheet is secured against primary liquid pressure, but which allows for easy removal of the tube section. The tube section is supported by a flange which is secured by a number of shear blocks, each of which extends into a slot which is immovable with respect to the outer shell of the heat exchanger.

Flow distribution for heat exchangers

Abstract: A heat exchanger where one fluid is flowed over tubes carrying another fluid to place said fluid in indirect heat exchange in which problems of erosion, temperature gradient, and vibrations at the area where the tubes are joined to a tube sheet are eliminated. A fluid inlet spaced from the tube sheet feeds fluid into an annular flow chamber which encircles the tubes and has an annular perforated plate closer to the tubes than the inlet and perforated so that the resistance to flow of fluid through the plate at different locations on it is a function of the distance from the inlet.

A study of boiling and condensation in a heat transfer element

Abstract: Test data are shown on the heat transfer during simultaneous boiling and condensation in a closed channel, whereupon recommendations are made for the design of heat transfer elements.

Simulation studies of a heat exchanger

Abstract: A shell-and-tube heat exchanger is to be modelled by digital simulation techniques using a lumpedparameter approximation. Contrast the results of this simulation with the more rigorous finite difference solution of the distributed-parameter model. The utility of both methods for simulation of exchanger dynamics is to be compared with experimentaZZz~ obtained data from a physical model of the system.